1. Field of the Invention
The present invention relates to a method for washing components or products, and in particular, to a method for washing optical components.
2. Description of the Related Art
Conventionally, in view of environmental conservation, a variety of methods for washing optical components using pure water have been proposed. For example, a prior art washing method using pure water is disclosed in U.S. Pat. No. 5,334,258 will be described with reference to a flowchart shown in FIG. 1. The process of the washing method shown in FIG. 1 is as follows.
a. Degreasing
This is a process for removing greasy stains (pitch, protecting film, cutting oil, etc.) by dipping the object to be washed in ethylene or a similar substance.
b. Substituting Water System
This is a process for preventing the greasy components of the above process of "a. degreasing" from entering a finish washing process as described below by dipping the object to be washed in an emulsifier.
c. Finish Washing
This is a process for removing a hydrophilic stain by dipping the object to be washed in a detergent.
d. Rinsing
This is a process for removing a residue of the above process of "c. finish washing" by dipping the object to be washed in pure water. The resistivity of the pure water to be used is not smaller than 10.0M.OMEGA..multidot.cm.
e. Finish Rinsing
This is a process for removing particulates and ions attached or left on the surface of the object to be washed by dipping the object to be washed in pure water. The resistivity of the pure water to be used is not smaller than 10.0M.OMEGA..multidot.cm.
f. Dipping Into Hot Pure Water
This is a process for dipping the object to be washed in a heated hot pure water. This process heats a glass, or the object to be washed up to a temperature at which a surface tension capable of uniformly drying the glass surface can be obtained. The resistivity of the pure water to be used is 10.0M.OMEGA..multidot.cm.
g. Taking Out From Hot Pure Water
This is a process for taking the object to be washed out of the pure water used in the above process. At the temperature maintained in the above process of "f. dipping into hot pure water," the object to be washed is taken out at a speed capable of uniformly draining off liquid.
h. Drying
This is a process comprised of a hot air zone and a cooling zone and effects to evaporate a moisture component left on the object to be washed that is taken out of the hot pure water and on the jig that is holding the object to be washed.
However, according to the aforementioned prior art washing method, chemical damage (hidden damage) may occur on the surface of the object to be washed, or in particular, of a glass component. Furthermore, expensive pure water has been used according to this prior art washing method, and this has consequently resulted in a cost increase.